The present invention relates generally to ironing machines and more specifically to an improved domer support assembly for such a machine.
In the formation of a "two-piece" container, a flat circular disc is normally transformed into a shallow cup using a cupping machine. The cup is then transferred to a bodymaker wherein the cup is converted into a finished container. The last step in producing the finished container consists of reforming the integral end wall of the container shell to increase the resistance of the container to internal pressures that are subsequently encountered when the container is utilized for packaging pressurized products.
One type of machine that has been utilized for producing containers of the above type is produced by Ragsdale Bros., Inc. and is identified as a Model CR-24 can wall drawing and ironing press. This machine includes a plurality of cooperating axially spaced die assemblies that cooperate with an axially movable punch to convert a cup into a finished drawn and ironed container. At the end of the stroke for the punch, the free end of the punch cooperates with a domer assembly for producing the final configuration of the integral end wall of the container. Usually such end wall configuration is domed inwardly as, for example, is shown in U.S. Pat. No. 3,942,673.
One of the problems that has been encountered is the misalignment with the free end of the punch and the domer or reforming member as the end wall is being reformed. It will be appreciated that the domer member must be spaced from the drawing and ironing die assemblies by a dimension which is greater than the axial length of the can so that the stripper ring positioned adjacent the die assemblies will be located above the free edge of the container to assist in removing the container from the punch or ram during the return stroke thereof. Thus, the domer element must be supported by as much as 6 inches away from the stripper assembly and this substantial spacing produces problems in maintaining an accurate alignment between the axis of the punch and the center of the domer member. If either of these members are misaligned by even a small dimension, defects occur in the reformed end wall, such as sharp indentations along one side of the inner edge of the end wall adjacent the sidewall thereof. This might in turn reduce the strength of the end wall even though the defects may not be visible.
It has also been determined that, when cups are initially misfed or defective cups are received in the drawing and ironing machine, the cups will be crushed by the punch during its movement through the redraw and ironing rings. In many instances, the crushed cup covers only a portion of the punch and will force the punch out of alignment with the center of the domer. Thus, the exposed portion of the punch may be damaged when it bottoms out on the domer. Also, many times the metal fragments are deposited on the domer which can also cause damage to the punch, particularly when the punch is formed from carbide material.